The background of the invention will be discussed in two parts:
1. Field of the Invention
This invention relates to wheel assemblies and more particularly to a wheel assembly for a skateboard, roller skate, or the like.
2. Description of the Prior Art
With the rapid rise in popularity of the sport of skateboarding, many different types of construction of skateboards, skateboard trucks and wheels have been developed. Due to competitive skateboard events, speeds have increased and numerous refinements have been made in construction materials as well as construction techniques. Speeds for general usage of skateboards average fifteen miles per hour while in pure speed events, skateboard riders have recorded speeds in excess of sixty miles per hour. Consequently, wheel construction has become increasingly important. The most readily available wheel construction has a urethane tire with a central aperture having press fit therein ball bearings, or alternatively, the tire is molded around the bearings. Another type of construction utilizing urethane wheels incorporates a metal race within the aperture for the utilization of loose ball bearings. In either of these two constructions, the metallic portion comprises a diameter which is relatively small compared to the overall diameter of the wheel resulting in a thick tire. With construction of this type, at high speeds, the bearing portion tends to separate from the surrounding urethan due to the repeated flexing, and either effects slippage between the tire and the bearing portion, misalignment of the bearing with respect to the tire or complete separation of the tire from the bearing, resulting in unstable or unsafe operating conditions.
Furthermore, with current tires having very thick urethane construction, in order to provide such tires with sufficient traction, they are made of a very soft urethane material. That material deforms at rolling speeds just ahead of the contact point of the tire with the surface upon which it is rolling, resulting in the material bunching up or bulging forward during the rolling. As the material deforms and reforms, internal heat is being generated through internal friction, thereby slowing the wheel down.
Another wheel construction currently on the market is sold by Apex Sports Products of La Mirada, Calif., and is shown in the magazine "Skateboarder", Volume 3, No. 1, which has been submitted to the Patent Office by separate communication. This wheel assembly incorporates a larger diameter hub resulting in a thinner tire, which is secured to the hub by molding or bonding. The tire is non-removable and made from a harder composition of urethane. If it is chipped, gouged, scraped or worn out, the entire wheel must be replaced.